1. Field of the Invention
The present invention relates to a structure of a sheet, or of a broad thin piece of material in the form of a sheet which is air-permeable and through which anything is substantially not seen at a front or rear side of the sheet.
2. Prior Art
Advertising material is often provided directly on buildings themselves. For example, at department stores or large-scale store buildings an advertising banner is used as an advertisement media to be suspended from the roof onto the outer wall, which is cheaper to install and has excellent workability in removal and replacement, among various types of advertisement provided in the similar manner, such as advertising balloons, large signboards, electric bulletin boards, special painting on the outer wall of buildings, or the like.
The advertising material in the form of a sheet is generally set outside the buildings and has a defect as likely affected by winds. The banner suspended from the building roof onto the outer wall may be gotten turned up or twisted even by a gentle wind, whereby advertisement provided or shown on the banner is put out of sight and ropes tightening the banner are disconnected or torn off, occasionally causing serious accidents.
The sheet material is used also for various portable tents for changing clothes, showering or getting sunshade on the beach or the like crowded with many people. The sheet material used for the tents is generally not of air-permeability and users feel uncomfortable in the tent. An opening which may be provided for ventilation in the tent will be closed when users change clothes, resulting in the change of clothes under a poor or uncomfortable circumstance.
The material in the form of a sheet, such as fabric for the above advertising banner and the tents, or others, when used to divide a space, does not at all provide sight through the material. For example, the advertising banner, when suspended from the roof onto the outer wall as covering any windows of the building, hinders any views from being afforded through the windows. Similarly, the foregoing tents even when set up at a location with a fine view do not allow users to enjoy the view from the inside of the tents while simultaneously preventing people outside the tent from looking inside.